1. Field of the Invention
This invention relates to an apparatus for stamping a monofilament of synthetic resin for slide fastener coupling elements, and more particularly to a stamping apparatus for continuously providing on monofilament coupling head portions, leg turnover portions, deformed portions facilitating bending, grooves receptive of sewing threads, etc. of side fastener coupling elements.
2. Description of the Related Art
An apparatus for stamping a monofilament for a coiled slide fastener coupling element is known from, for example, Japanese Patent Publication 8902/1988. In the known apparatus, as shown in FIGS. 4 to 6, a monofilament G is continuously stamped by a pair of stamping rollers E, E as the monofilament G is supplied between the rollers E, E through a guide hole in a rotary member D rotatably disposed on a stationary shaft B and having a mandrel extending from one of its ends, so that a stamped monofilament C is wound around the rotary member D.
However, in this prior art apparatus, since the monofilament is supplied solely by the stamping rollers, the monofilament will not be uniformly carried depending upon its amount remaining on a bobbin, or vibrations applied to a monofilament feeding path, which will result in irregularly stamped positions on and along the monofilament. In addition, since the stamping teeth H bite into the monofilament abruptly, cracks tend to develop in shaped portions. And since the stamping teeth are separated from the monofilament suddenly after having compressed the monofilament, the pressing time is not sufficient to cure the individual shaped portion in a correct contour. Therefore it is difficult to always obtain the shaped portions with accuracy.